1. Field of the Invention
The present invention relates to a fiducial marker using a biodegradable multi-block copolymer.
2. Description of the Prior Art
In external-beam radiotherapy, the degree of correspondence between the radiation beam angle and a target object is important in order to provide an accurate dose to a tumor location as much as possible. Especially, in the case of patients with lung cancer or liver cancer strongly affected by respiration, it is difficult to accurately apply radiation to tumors due to motion of organs due to the respiration. Therefore, it is important to establish the therapeutic plan considering the motion of tumors due to respiration, in order to increase the success rate of radiotherapy on moving organs. At the time of actual treatment, the accuracy of radiotherapy is improved by real-time tracing the motion of a marker inserted in the human body to accurately and promptly trace the motion of organs.
For these aims, gold markers easily recognizable on images are used in actual radiotherapy, but a metal material has disadvantages in that X-rays increase image distortion and dose distortion. The image distortion makes it hard to determine a target and surrounding organs on images, causing inaccuracy at the time of delineating a target and a region of interest (ROI), and the determination of the marker position is actually affected by radiographic visibility and computed tomography (CT) image artifacts, so the marker position may be shown differently.
As for proton therapy, the therapy range by Bragg peak is important. However, according to existing study results, the dose distortion occurs around a gold marker when the direction of the proton beam is set to pass through the gold marker. In order to reduce such dose distortion, researches on the diminishment in the dose distortion through the mixing of gold nanoparticles and bone cement has been conducted.
Accordingly, the present invention aims to develop a fiducial marker that has excellent identifiability on medical images and minimized mobility in biological tissues by combining a contrast agent material and a biodegradable polymer material.
Throughout the entire specification, many papers and patent documents are referenced and their citations are represented. The disclosure of cited papers and patent documents are entirely incorporated by reference into the present specification, and the level of the technical field within which the present invention falls and details of the present invention are explained more clearly.